Question: Solve: $\dfrac{7}{8} - \dfrac{1}{4} - \dfrac{1}{2} = $
Explanation: Let's look at the multiples of each denominator and see which multiples they have in common. Denominator Multiples ${8}$ $\underline{{8}}, 16, 24$ ${4}$ $4, \underline{{8}}, 12$ ${2}$ $2, 4, 6, \underline{{8}}$ The least common multiple is ${8}$. Let's use multiplication to make each fraction have a denominator of $8$. $\begin{aligned} &{\dfrac{7}{8}}\\\\ &{\dfrac{1}{4}}=\dfrac{{1} \times 2}{{4} \times2} = {\dfrac{2}{8}}\\\\ &{\dfrac{1}{2}}=\dfrac{{1} \times 4}{{2} \times4} = {\dfrac{4}{8}} \end{aligned}$ $\begin{aligned} &{\dfrac{7}{8}} - {\dfrac{1}{4}} - {\dfrac{1}{2}}\\\\ =& {\dfrac{7}{8}} - {\dfrac{2}{8}} - {\dfrac{4}{8}}\\\\ =&\dfrac{{7} - {2} - {4}}{8}\\\\ =&\dfrac{5-{4}}{8}\\\\ =&\dfrac18 \end{aligned}$ ${\dfrac{7}{8}} - {\dfrac{1}{4}} - {\dfrac{1}{2}} = \dfrac{1}{8}$